NEVER use the crow bar to pry in a upward motion, the whole tank wall will separate from the base!  You are trying to pry the mold in, not up or out! 

The GOOD NEWS: Once the section is free, you have won the battle (hopefully with out too much damage to the tank), carefully hand the mold section out to some one on the outside. Be sure not to bang the lip of the tank with the mold when passing it over the wall. 

DO NOT WORRY, the hair line cracks can be removed with a cement - sand paste! The other sections are removed in the same manner but will come out much easier.

3. Once all the sections of the mold are handed out of the tank, hand in a broom, trowel, and float for the inside guy and store the crowbar or chisel, wrenches and hammer. 

The inside guy will need to sweep up inside the tank and toss out the dried cement that is on the floor. 

Clean it up well so that there isn't a lot of junk (dried cement chunks) that gets into your new cement mix.
The person on the inside will begin to CAREFULLY enlarge the hole for the pipe nipple (using a screwdriver and/or tip of his trowel). The hold should be about 4 inches from the base. Hand him the metal tube with the butterfly cut on the end. 

He will place it into the hole when the hole is large enough. The butterfly  will hold the tube firmly in the wall once the inside walls of cement are made. Try to make sure the tube is fairly level. 

Then with the float cover the butterfly with mix.  Don´t worry about filling it with cement, this will come out easy the next morning.

Have some one on the outside must pack a little cement mix around the tube as show in the photo. The threads should then be cleaned off with a little water! Use a sponge or the paint brush.